1. Field of the Invention
The present invention relates in general to Global Satellite System (GSS) receivers, and in particular to multi-mode Global Positioning System (GPS) for use with wireless networks.
2. Description of the Related Art
Cellular telephony, including Personal Communication System (PCS) devices, has become commonplace. The use of such devices to provide voice, data, and other services, such as internet access, has provided many conveniences to cellular system users. Further, other wireless communications systems, such as two-way paging, trunked radio, Specialized Mobile Radio (SMR) that is used by police, fire, and paramedic departments, have also become essential for mobile communications.
A current thrust in the cellular and PCS arena is the integration of Global Positioning System (GPS) technology into cellular telephone devices and other wireless transceivers. For example, U.S. Pat. No. 5,874,914, issued to Krasner, which is incorporated by reference herein, describes a method wherein the basestation (also known as the Mobile Telephone Switching Office (MTSO)) transmits GPS satellite information, including Doppler information, to a remote unit using a cellular data link, and computing pseudoranges to the in-view satellites without receiving or using satellite ephemeris information.
This current interest in integrating GPS with cellular telephony stems from a new Federal Communications Commission (FCC) requirement that cellular telephones be locatable within 50 feet once an emergency call, such as a xe2x80x9c911xe2x80x9d call (also referred to as xe2x80x9cEnhanced 911xe2x80x9d or xe2x80x9cE911xe2x80x9d) is placed by a given cellular telephone. Such position data assists police, paramedics, and other law enforcement and public service personnel, as well as other agencies that may need or have legal rights to determine the cellular telephone""s position. Further, GPS data that is supplied to the mobile telephone can be used by the mobile telephone user for directions, latitude and longitude positions Locations or positions) of other locations or other mobile telephones that the cellular user is trying to locate, determination of relative location of the cellular user to other landmarks, directions for the cellular user via internet maps or other GPS mapping techniques, etc. Such data can be of use for other than E911 calls, and would be very useful for cellular and PCS subscribers.
The approach in Krasner, however, is limited by the number of data links that can be connected to a GPS-dedicated data supply warehouse. The system hardware would need to be upgraded to manage the additional requirements of delivering GPS information to each of the cellular or PCS users that are requesting or requiring GPS data, which requirements would be layered on top of the requirements to handle the normal voice and data traffic being managed and delivered by the wireless system.
Another patent that concerns assistance between the GPS system and wireless networks is U.S. Pat. No. 5,365,450, issued to Schuchman, et al. which is incorporated by reference herein. In the Schuchman reference, ephemeris aiding through the cellular telephone system is required for the GPS receiver to acquire and track GPS satellites. However, cellular and other wireless networks do not always have the capability to provide ephemeris aiding to the mobile GPS receiver.
It can be seen, then, that there is a need in the art for delivering GPS data to wireless communications systems, including cellular and PCS subscribers, in an efficient manner. It can also be seen that there is a need in the art for GPS capable cellular and PCS telephones. It can also be seen that there is a need in the art for GPS capable cellular and PCS telephones that can receive GPS satellite data for use by the cellular/PCS subscriber. It can also be seen that there is a need in the art for a,large cellular system that can use and/or supply GPS information to cellular users for a number of applications, including E911 without the requirement of geographically proximate basestations.
To minimize the limitations in the prior art described above, and to minimize other limitations that will become apparent upon reading and understanding the present specification, the present invention discloses a system, device, and method for determining the position of a mobile device. The system comprises a geolocation server and a wireless communications device. The geolocation server receives at least one signal from at least one GPS satellite. The wireless communications device comprises a GPS receiver section, wherein the GPS receiver can be selectively switched between a standalone mode and at least one other mode for determining a geolocation of the wireless communications device. The wireless communication device can selectively send the determined geolocation of the wireless communication device to the geolocation server, and the wireless communications device periodically transmits a frequency reference message to the GPS receiver.
It is an object of the present invention to provide a method and a system for delivering GPS data to wireless communications systems, including cellular and PCS subscribers in an efficient manner. It is another object of the present invention to provide a method and a system that can manage GPS capable cellular and PCS telephones. It is another object of the present invention to provide a method and a system for GPS capable cellular and PCS telephones that can receive GPS satellite data for use by the cellular/PCS subscriber. It is a further object of the present invention to provide a method and a system for large cellular systems to use that can use and/or supply GPS information to cellular users for a number of applications, including E911.